Revert of [Service Manager] Get rid of dynamic service discovery

services/catalog/reader.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SERVICES_CATALOG_READER_H_
+#define SERVICES_CATALOG_READER_H_
+
+#include <map>
+#include <memory>
+#include <string>
+
+#include "base/callback.h"
+#include "base/files/file_path.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "services/service_manager/public/interfaces/resolver.mojom.h"
+
+namespace base {
+class SequencedWorkerPool;
+class SingleThreadTaskRunner;
+class Value;
+}
+
+namespace catalog {
+
+class Entry;
+class EntryCache;
+class ManifestProvider;
+
+// Responsible for loading manifests & building the Entry data structures.
+class Reader {
+ public:
+  using ReadManifestCallback = base::Callback<void(std::unique_ptr<Entry>)>;
+  using CreateEntryForNameCallback =
+      service_manager::mojom::Resolver::ResolveServiceNameCallback;
+
+  // Construct a Reader over a static manifest. This Reader never performs
+  // file I/O.
+  Reader(std::unique_ptr<base::Value> static_manifest, EntryCache* cache);
+
+  Reader(base::SequencedWorkerPool* worker_pool,
+         ManifestProvider* manifest_provider);
+  Reader(base::SingleThreadTaskRunner* task_runner,
+         ManifestProvider* manifest_provider);
+  ~Reader();
+
+  // Scans the contents of |package_dir|, reading all application manifests and
+  // populating |cache|. Runs |read_complete_closure| when done.
+  void Read(const base::FilePath& package_dir,
+            EntryCache* cache,
+            const base::Closure& read_complete_closure);
+
+  // Returns an Entry for |name| via |callback|, assuming a manifest file in the
+  // canonical location
+  void CreateEntryForName(
+      const std::string& name,
+      EntryCache* cache,
+      const CreateEntryForNameCallback& entry_created_callback);
+
+  // Overrides the package name used for a specific service name.
+  void OverridePackageName(const std::string& service_name,
+                           const std::string& package_name);
+
+  // Overrides the manifest path used for a specific service name.
+  void OverrideManifestPath(const std::string& service_name,
+                            const base::FilePath& path);
+
+ private:
+  explicit Reader(ManifestProvider* manifest_provider);
+
+  void OnReadManifest(EntryCache* cache,
+                      const CreateEntryForNameCallback& entry_created_callback,
+                      std::unique_ptr<Entry> entry);
+
+  const bool using_static_catalog_ = false;
+  base::FilePath system_package_dir_;
+  scoped_refptr<base::TaskRunner> file_task_runner_;
+  ManifestProvider* const manifest_provider_;
+  std::map<std::string, std::string> package_name_overrides_;
+  std::map<std::string, base::FilePath> manifest_path_overrides_;
+  base::WeakPtrFactory<Reader> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(Reader);
+};
+
+}  // namespace catalog
+
+#endif  // SERVICES_CATALOG_READER_H_